Brave woman's cut short drug (6)
I believe the answer is:
heroin
'drug' is the definition.
(heroin is a kind of drug)
'brave woman's cut' is the wordplay.
'brave woman' becomes 'heroine' (I've seen this before).
'cut' means to remove the last letter.
'heroine' with its final letter removed is 'HEROIN'.
'short' acts as a link.
(Other definitions for heroin that I've seen before include "Highly addictive illegal drug" , "Highly addictive morphine derivative" , "Hard drug" , "Class A drug" , "Type of drug" .)